% test function
% x belongs to [a,b]
% x=(a+b)/2+(b-a)*t/2
function y = Schaffer(a,b,t1,t2)
    x=(a+b)/2+(b-a)*t1/2;
	y = 0.5 + (sin(sqrt(t1^2+t2^2))^2-0.5)/(1+0.001*(t1^2+t2^2));
end